Magnetic assembly and power supply system with same

ABSTRACT

A magnetic assembly includes plural first magnetic cores, plural coil windings and a second magnetic core. Each of the plural first magnetic cores includes plural legs and a first connection part. The first connection part is connected with first terminals of the plural legs. The first connection part of the first magnetic core at an upper position is located adjacent to second terminals of the plural legs of the adjacent first magnetic core at a lower position. Each coil winding is wound around at least one leg of the plural legs of the corresponding first magnetic core so as to form a magnetic element of the corresponding converter. The second magnetic core is stacked over the plural first magnetic cores. The second magnetic core is located adjacent to the second terminals of the legs of the topmost first magnetic core.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional Application of U.S. patent applicationSer. No. 14/970,174 filed on Dec. 15, 2015 and entitled “MAGNETICASSEMBLY AND POWER SUPPLY SYSTEM WITH SAME”, which claims priority toChina patent application No. 201520495224.4 filed on Jul. 9, 2015 andentitled “MAGNETIC ASSEMBLY AND POWER SUPPLY SYSTEM WITH SAME”, theentirety of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a magnetic assembly, and moreparticularly to a magnetic assembly with reduced magnetic loss, volume,weight and cost. The present invention also relates to a power supplysystem with the magnetic assembly.

BACKGROUND OF THE INVENTION

Generally, plural converters are connected with each other in parallelin a power supply system when high power is required. Each convertercomprises at least one magnetic element such as a transformer or aninductor. The magnetic element comprises a magnetic core and a coilwinding. The coil winding is wound around the magnetic core to form aclosed magnetic flux path. Consequently, the magnetic element isproduced.

Since the magnetic element occupies large fractions of volume and weightof the overall power supply system, it is an important issue to reducethe volume and weight of the magnetic element in order to increase thepower density of the power supply system. However, since the magneticelements of the plural converters have individual magnetic cores and themagnetic flux paths are independent, the volume and weight of theoverall power supply system are increased and the fabricating cost ofthe power supply system is high. Moreover, during operations of thepower supply system, the magnetic core of the magnetic element of eachconverter will result in a large magnetic loss. Since the magnetic coresof the magnetic elements of the plural converters in the conventionalpower supply system are independent and the magnetic flux paths areindependent, the conventional power supply system has large magneticloss and volume.

Therefore, there is a need of providing a magnetic assembly and a powersupply system with the magnetic assembly in order to overcome the abovedrawbacks.

SUMMARY OF THE INVENTION

An object of the present invention provides a magnetic assembly and apower supply system with the magnetic assembly. The magnetic assemblyintegrates plural magnetic elements. Consequently, the volume and weightof the magnetic assembly have been reduced, and the power supply systemhas reduced cost and increased power density.

In accordance with an aspect of the present invention, there is provideda magnetic assembly for plural parallel-connected converters. Themagnetic assembly includes plural first magnetic cores, plural coilwindings and a second magnetic core. The plural first magnetic cores arestacked over each other from bottom to top. Each of the plural firstmagnetic cores includes plural legs and a first connection part. Thefirst connection part is connected with first terminals of the plurallegs. The first connection part of the first magnetic core at an upperposition is located adjacent to second terminals of the plural legs ofthe adjacent first magnetic core at a lower position. Each coil windingis wound around at least one leg of the plural legs of the correspondingfirst magnetic core so as to form a magnetic element of thecorresponding converter. The second magnetic core is stacked over theplural first magnetic cores. The second magnetic core is locatedadjacent to the second terminals of the legs of the topmost firstmagnetic core.

In accordance with another aspect of the present invention, there isprovided a power supply system. The power supply system includes pluralconverters. The plural converters are connected with each other inparallel. The plural converters receive an input voltage and convert theinput voltage into an output voltage. The plural converters include atleast one magnetic assembly. The magnetic assembly includes plural firstmagnetic cores, plural coil windings and a second magnetic core. Theplural first magnetic cores are stacked over each other from bottom totop. Each of the plural first magnetic cores includes plural legs and afirst connection part. The first connection part is connected with firstterminals of the plural legs. The first connection part of the firstmagnetic core at an upper position is located adjacent to secondterminals of the plural legs of the adjacent first magnetic core at alower position. Each coil winding is wound around at least one leg ofthe plural legs of the corresponding first magnetic core so as to form amagnetic element of the corresponding converter. The second magneticcore is stacked over the plural first magnetic cores. The secondmagnetic core is located adjacent to the second terminals of the legs ofthe topmost first magnetic core.

From the above descriptions, the present invention provides a magneticassembly and a power supply system with the magnetic assembly. Themagnetic assembly comprises plural magnetic elements of pluralconverters. Moreover, portions of the magnetic core of the magneticelements and magnetic flux paths are shared. Consequently, the volumeand weight of the magnetic assembly of the power supply system have beenreduced. Under this circumstance, the fabricating cost of the magneticelements is reduced, and the power density of the power supply system isincreased.

The above contents of the present invention will become more readilyapparent to those ordinarily skilled in the art after reviewing thefollowing detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic circuit diagram illustrating a power supply systemaccording to a first embodiment of the present invention;

FIG. 2 schematically illustrates an exemplary magnetic assembly used inthe power supply system of FIG. 1;

FIG. 3 schematically illustrates the flows of the magnetic fluxes in themagnetic assembly of FIG. 2;

FIG. 4 schematically illustrates a variant example of the magneticassembly of FIG. 2;

FIG. 5 schematically illustrates a further variant example of themagnetic assembly of FIG. 2;

FIG. 6 schematically illustrates a still variant example of the magneticassembly of FIG. 1;

FIG. 7 schematically illustrates a variant example of the magneticassembly of FIG. 6;

FIG. 8 is a schematic circuit diagram illustrating a power supply systemaccording to a second embodiment of the present invention; and

FIG. 9 schematically illustrates a magnetic assembly used in the powersupply system of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this invention arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

In this context, the term “equal” indicates a certain tolerance. Forexample, the tolerance is 20%, preferably 10%, and more preferably 5%.

In this context, each of the first coil winding and the second coilwinding is composed of one coil winding or plural coil windingsaccording to the practical requirements.

Moreover, the plural converters are connected with each other inparallels. In particular, the input terminals and/or the outputterminals of the converters are connected with each other in parallel.

FIG. 1 is a schematic circuit diagram illustrating a power supply systemaccording to a first embodiment of the present invention. FIG. 2schematically illustrates a magnetic assembly used in the power supplysystem of FIG. 1. As shown in FIGS. 1 and 2, the power supply system 1comprises plural converters, which are connected with each other inparallel. Preferably but not exclusively, plural converters comprise afirst converter 31, a second converter 32 and a third converter 33.These converters 31, 32 and 33 receive an input voltage V_(in) andconverting the input voltage V_(in) into an output voltage V_(o).Preferably but not exclusively, the converters 31, 32 and 33 are boostconverters.

In this embodiment, the first converter 31 comprises a first magneticelement, a first switch element S₁ and a first diode D₁. The firstmagnetic element corresponds to the inductor or the transformer of thefirst converter 31. For example, in case that the first converter 31 isa boost converter, the first magnetic element is a first inductor L₁. Afirst terminal a₁ of the first inductor L₁ is electrically connectedwith an input terminal of the power supply system 1 for receiving theinput voltage V_(in) and storing or releasing the received electricenergy. A second terminal b₁ of the first inductor L₁ is electricallyconnected with a first terminal of the first switch element S₁. A secondterminal of the first switch element S₁ is electrically connected with aground terminal. An anode of the first diode D₁ is electricallyconnected with the second terminal b₁ of the first inductor L₁ and thefirst terminal of the first switch element S₁. A cathode of the firstdiode D₁ is electrically connected with an output terminal of the powersupply system 1.

The circuitry configurations of the second converter 32 and the thirdconverter 33 are similar to the circuitry configuration of the firstconverter 31. The second converter 32 comprises a second inductor L₂, asecond switch element S₂ and a second diode D₂. The third converter 33comprises a third inductor L₃, a third switch element S₃ and a thirddiode D₃. The functions and relationships of the second inductor L₂, thesecond switch element S₂ and the second diode D₂ and the functions andrelationships of the third inductor L₃, the third switch element S₃ andthe third diode D₃ are similar to those of the first inductor L₁, thefirst switch element S₁ and the first diode D₁, and are not redundantlydescribed herein. It is noted that the number of the converters in thepower supply system 1 is not restricted to three. That is, the number ofthe converters in the power supply system 1 may be varied according tothe practical requirements.

FIG. 2 schematically illustrates an exemplary magnetic assembly used inthe power supply system of FIG. 1. In this embodiment, an integratedmagnetic assembly 2 (also referred hereinafter as a magnetic assembly)comprises the first inductor L₁, the second inductor L₂ and the thirdinductor L₃. The magnetic assembly 2 comprises plural first magneticcores 21, plural coil windings 22 and a second magnetic core 23. In thisembodiment, the magnetic assembly 2 comprises three first magnetic cores21, three coil windings 22 and a second magnetic core 23. Each firstmagnetic core 21 comprises plural legs 11 and a first connection part26. The first terminals of the plural legs 11 are connected with thefirst connection part 26.

Please refer to FIG. 2 again. The plural first magnetic cores 21 arestacked over each other from bottom to top. Consequently, the firstconnection part 26 of the upper first magnetic core 21 is locatedadjacent to the second terminals of the plural legs 11 of the adjacentlower first magnetic core 21. Moreover, each coil winding 22 is woundaround one leg 11 of the corresponding first magnetic core 21.Consequently, the plural first coil windings 22 are formed as the coilwindings of the inductors L₁, L₂ and L₃ of the converters 31, 32 and 33,respectively. In this embodiment, the first terminals a₁, a₂ and a₃ ofthe three first coil windings 22 correspond to the first terminal a₁ ofthe first inductor L₁, the first terminal a₂ of the second inductor L₂and the first terminal a₃ of the third inductor L₃, respectively.Moreover, the second terminals b₁, b₂ and b₃ of the three first coilwindings 22 correspond to the second terminal b₁ of the first inductorL₁, the second terminal b₂ of the second inductor L₂ and the secondterminal b₃ of the third inductor L₃, respectively. In some embodiment,each first coil winding 22 is composed of plural coil windings, and theplural coil windings are collaboratively wound around one leg 11 of thecorresponding first magnetic core 21. Consequently, the plural firstcoil windings 22 are formed as the coil windings of the inductors L₁, L₂and L₃ of the converters 31, 32 and 33, respectively. The secondmagnetic core 23 is stacked over the plural first magnetic cores 21.Consequently, a first side 230 of the second magnetic core 23 is locatedadjacent to the second terminals of the legs 11 of the topmost firstmagnetic core 21.

In the embodiment of FIG. 2, the plural legs 11 of each first magneticcore 21 comprise a first central leg 24 and two first side legs 25. Thetwo first side legs 25 are opposed to each other with relative to thefirst central leg 24. Moreover, the distance between one first side leg25 and the first central leg 24 is equal to the distance between theother first side leg 25 and the first central leg 24. In each firstmagnetic core 21, the first connection part 26 is connected with thefirst terminal 241 of the first central leg 24 and the first terminals251 of the two first side legs 25. Moreover, the plural first magneticcores 21 are stacked over each other from bottom to top. Consequently,the first connection part 26 of the upper first magnetic core 21 islocated adjacent to the second terminal 242 of the first central leg 24and the second terminals 252 of the two first side legs 25 of theadjacent lower first magnetic core 21. For supporting the upper firstmagnetic core 21, the spaces between the second terminal 242 of thefirst central leg 24 and the second terminals 252 of the two first sidelegs 25 of the lower first magnetic core 21 and the first connectionpart 26 of the upper first magnetic core 21 may be filled with aninsulation material. In this embodiment, each first coil winding 22 iswound around the first central leg 24 of the corresponding firstmagnetic core 21. Moreover, the first side 230 of the second magneticcore 23 is located adjacent to the second terminal 242 of the firstcentral leg 24 and the second terminals 252 of the two first side legs25 of the topmost first magnetic core 21.

In this embodiment, the first central leg 24, the two first side legs 25and the first connection part 26 of each first magnetic core 21 arecollaboratively formed as an E-shaped core, and the second magnetic core23 is an I-shaped core. It is noted that the number of the firstmagnetic cores 21 and the number of the first coil windings 22 may bevaried according to the practical requirements.

FIG. 3 schematically illustrates the flows of the magnetic fluxes in themagnetic assembly of FIG. 2. During operations of the power supplysystem 1, the converters 31, 32 and 33 receive the input voltage V_(in).Consequently, electric currents flow through the first coil windings 22wounding around the first central legs 24 of the three first magneticcores 21 of the magnetic assembly 2, and magnetic fluxes Φ₁, Φ₂ and Φ₃are generated thereof, respectively. Since the electric currents flowingthrough the first coil windings 22 are in the same direction, themagnetic fluxes (Φ₁, Φ₂ and Φ₃ flow in the directions indicated by thedotted lines. In particular, the magnetic fluxes (Φ₁, Φ₂ and Φ₃ flowingthrough the first central legs 24 of the three first magnetic cores 21are in the same direction (i.e., in the upward direction). Moreover,each of the magnetic fluxes Φ₂ and Φ₃ flows through the bilateral sidesof the first connection part 26 of the upper first magnetic core 21, thetwo first side legs 25 of the corresponding first magnetic core 21 andthen the first connection part 26 of the corresponding first magneticcore 21 and returns to the first central leg 24. The magnetic flux Φ₁flows through the bilateral sides of the second magnetic cores 23, thetwo first side legs 25 of the corresponding first magnetic core 21 andthen the first connection part 26 of the corresponding first magneticcore 21 and returns to the first central leg 24. As mentioned above, theelectric currents flow through the first coil windings 22 of the threefirst magnetic cores 21 of the converters 31, 32 and 33 in the samedirection. Consequently, in every two adjacent first magnetic cores 21,the magnetic fluxes through the first connection part 26 of the upperfirst magnetic core 21 are in opposite directions. As shown in FIG. 3,plural zones A are formed in the first connection part 26 of the upperfirst magnetic core 21. The magnetic fluxes in the zones A of the sharedfirst connection part 26 are canceled by each other. That is, portionsof the magnetic fluxes of every two adjacent first magnetic cores 21 canbe canceled by each other. Consequently, the peak flux density isreduced. Under this circumstance, the cross section area of the firstconnection part 26 can be reduced.

More especially, if the electric currents flow through the first coilwindings 22 wounding around the first central legs 24 of the three firstmagnetic cores 21 of the converters 31, 32 and 33 are equal to eachother, the magnetic fluxes through the first connection part 26 of theupper first magnetic core 21 can be completely canceled. Under thiscircumstance, the peak flux density is further reduced, and the crosssection area of the first connection part 26 is further reduced.

In one embodiment, adjusts the inductance values of the inductors L₁, L₂and L₃ to be equal, to make the electric currents flowing through thefirst coil windings 22 wounding around the three first magnetic cores 21of the converters 31, 32 and 33 to be equal. In one embodiment, adjuststhe turns of the first coil windings 22 to be equal, to make theinductance values of the inductors L₁, L₂ and L₃ to be equal. In oneembodiment, the lengths of the two side legs 25 of each first magneticcore 21 are equal. So the assembling process is simplified, and themagnetic fluxes are distributed more uniformly to forbid partialsaturation. More preferably, the lengths of the two side legs 25 of eachfirst magnetic core 21 are equal, and the first central leg 24 of eachfirst magnetic core 21 has the same length. That is, each first magneticcore 21 is symmetrical. Consequently, the assembling process issimplified, and to make the inductance values of the inductors L₁, L₂and L₃ to be equal.

From the above descriptions, the plural inductors L₁, L₂ and L₃ of theplural converters 31, 32 and 33 are formed by the magnetic assembly 2,and portions of the magnetic flux paths of the first magnetic cores 21of the magnetic assembly 2 are shared. That is, portions of the firstconnection parts 26 of the first magnetic cores 21 are shared. Incomparison with the magnetic elements of the converters of theconventional power supply system having the independent magnetic coresand coil windings, the power supply system 1 of the present inventioncan largely reduce the volumes and weights of the magnetic elements.Moreover, since portions of the magnetic flux paths of the firstmagnetic cores 21 and the second magnetic core 23 of the magneticassembly 2 are shared to cancel the magnetic fluxes, the peak fluxdensity is reduced. Under this circumstance, the volume and weight ofthe magnetic element are further reduced, and the inductance values ofthe inductors L₁, L₂ and L₃ are equal. Consequently, the pluralparallel-connected converters 31, 32 and 33 can be controlled moreeasily.

Moreover, since the plural converters 31, 32 and 33 of the power supplysystem 1 are connected with each other in parallel and the circuitryconfigurations of the plural converters 31, 32 and 33 are similar, theoperating waveforms of the inductors L₁, L₂ and L₃ of the pluralconverters 31, 32 and 33 are identical. Moreover, during operations ofthe power supply system 1, the phases between the operating waveforms ofthe inductors L₁, L₂ and L₃ are identical to each other or shiftedrelative to each other.

FIG. 4 schematically illustrates a variant example of the magneticassembly of FIG. 2. The components of the magnetic assembly 3 and therelationships between these components are similar to those of themagnetic assembly 2 of the FIG. 2. Component parts and elementscorresponding to those of the FIG. 2 are designated by identical numeralreferences, and detailed descriptions thereof are omitted. In comparisonwith the I-shaped core of the second magnetic core 23 of FIG. 2, thesecond magnetic core 33 of this embodiment is an E-shaped core with asecond central leg 34, two second side legs 35 and a second connectionpart 36. The two second side legs 35 are opposed to each other withrelative to the second central leg 34. Moreover, the distance betweenone second side leg 35 and the second central leg 34 is equal to thedistance between the other second side leg 35 and the second central leg34. The second connection part 36 is connected with the first terminal341 of the second central leg 34 and the first terminals 351 of the twosecond side legs 35. The second magnetic core 33 is stacked over theplural first magnetic cores 21. Moreover, the second terminal 342 of thesecond central leg 34 and the second terminals 352 of the two secondside legs 35 are respectively located adjacent to the second terminal242 of the first central leg 24 and the second terminals 252 of the twofirst side legs 25 of the topmost first magnetic core 21. In oneembodiment, when the second magnetic core 33 is stacked over the pluralfirst magnetic cores 21, the first coil winding 22 wound around thefirst central leg 24 of the topmost first magnetic core 21 is alsopartially wound around the second central leg 34 of the second magneticcore 33.

FIG. 5 schematically illustrates a further variant example of themagnetic assembly of FIG. 2. The components of the magnetic assembly 3and the relationships between these components are similar to those ofthe magnetic assembly 2 of the FIG. 2. Component parts and elementscorresponding to those of the FIG. 2 are designated by identical numeralreferences, and detailed descriptions thereof are omitted. In thisembodiment, the magnetic assembly 4 comprises two first magnetic cores21, a second magnetic core 23 and a third magnetic core 41. Incomparison with the magnetic assembly 2 of FIG. 2, the magnetic assembly4 of this embodiment has less first magnetic core 21 but furthercomprises an additional third magnetic core 41. The third magnetic core41 is located beside a second side 231 of the second magnetic core 23.The third magnetic core 41 is an E-shaped core with a third central leg44, two third side legs 45 and a third connection part 46. Moreover, thethird magnetic core 41 is symmetrical to the first magnetic core 21 withrespect to the second magnetic core 23. The two third side legs 45 areopposed to each other with relative to the third central leg 44.Moreover, the distance between one third side leg 45 and the thirdcentral leg 44 is equal to the distance between the other third side leg45 and the third central leg 44. The third connection part 46 isconnected with the first terminal 441 of the third central leg 44 andthe first terminals 451 of the two third side legs 45. Moreover, thesecond terminal 442 of the third central leg 44 and the second terminals452 of the two third side legs 45 are located adjacent to a second side231 of the second magnetic core 23. Moreover, a first coil winding 22 iswound around the third central leg 44 of the third magnetic core 41 soas to form the coil winding of the first inductor L₁ of the firstconverter 31 (see FIG. 1). Consequently, the first terminal a₁ and thesecond terminal b₁ of the first coil winding 22 correspond to the firstterminal a₁ and the second terminal b₁ of the first inductor L₁ of FIG.1, respectively.

FIG. 6 schematically illustrates a still variant example of the magneticassembly of FIG. 1. In this embodiment, the magnetic assembly 6comprises plural first magnetic cores 51, plural coil windings 52 and asecond magnetic core 53. For example, the magnetic assembly 6 comprisesthree first magnetic cores 51, three coil windings 52 and a secondmagnetic core 53. Each first magnetic core 51 comprises plural legs 55and a first connection part 56. The first terminals 551 of the plurallegs 55 are connected with the first connection part 56.

Please refer to FIG. 6 again. The plural first magnetic cores 51 arestacked over each other from bottom to top. Consequently, the firstconnection part 56 of the upper first magnetic core 51 is locatedadjacent to the second terminals 552 of the plural legs 55 of theadjacent lower first magnetic core 51. Moreover, each coil winding 52 iswound around at least one leg 55 of the corresponding first magneticcore 51. Consequently, the plural first coil windings 52 are formed asthe coil windings of the inductors L₁, L₂ and L₃ of the converters 31,32 and 33, respectively. In this embodiment, the first terminals a₁, a₂and a₃ of the three first coil windings 52 correspond to the firstterminal a₁ of the first inductor L₁, the first terminal a₂ of thesecond inductor L₂ and the first terminal a₃ of the third inductor L₃,respectively. Moreover, the second terminals b₁, b₂ and b₃ of the threefirst coil windings 52 correspond to the second terminal b₁ of the firstinductor L₁, the second terminal b₂ of the second inductor L₂ and thesecond terminal b₃ of the third inductor L₃, respectively. The secondmagnetic core 53 is stacked over the plural first magnetic cores 51.Consequently, a first side 530 of the second magnetic core 53 is locatedadjacent to the second terminals 552 of the legs 55 of the topmost firstmagnetic core 51.

In the embodiment of FIG. 6, the plural legs 55 of each first magneticcore 51 comprise two first side legs. Moreover, each first coil winding52 is wound around the two first side legs of the corresponding firstmagnetic core 51. Moreover, the two first side legs and the firstconnection part 56 of each first magnetic core 51 are collaborativelyformed as a U-shaped core.

FIG. 7 schematically illustrates a variant example of the magneticassembly of FIG. 6. In comparison with FIG. 6, each first coil winding52 of the magnetic assembly 6 of this embodiment is wound around anyfirst side leg of the corresponding first magnetic core 51.

The technical features of the U-shaped cores shown in FIGS. 6 and 7 aresimilar to those of the above E-shaped cores, and are not redundantlydescribed herein.

FIG. 8 is a schematic circuit diagram illustrating a power supply systemaccording to a second embodiment of the present invention. FIG. 9schematically illustrates a magnetic assembly used in the power supplysystem of FIG. 8. As shown in FIGS. 8 and 9, the power supply system 7comprises plural converters, which are connected with each other inparallel. Preferably but not exclusively, plural converters comprise afirst converter 71, a second converter 72 and a third converter 73.These converters 71, 72 and 73 receive an input voltage V_(in) andconverting the input voltage V_(in) into an output voltage V_(o).Preferably but not exclusively, the converters 71, 72 and 73 are LLCresonant converters.

In this embodiment, the first converter 71 comprises a first switchelement S₁₁, a second switch element S₁₂, a capacitor C₁, a firstmagnetic element, a second magnetic element, a first diode D₁₁ and asecond diode D₁₂. The circuitry configurations of the second converter72 and the third converter 73 are similar to the circuitry configurationof the first converter 71. The second converter 72 comprises a firstswitch element S₂₁, a second switch element S₂₂, a capacitor C₂, a firstmagnetic element, a second magnetic element, a first diode D₂₁ and asecond diode D₂₂. The second converter 73 comprises a first switchelement S₃₁, a second switch element S₃₂, a capacitor C₃, a firstmagnetic element, a second magnetic element, a first diode Dai and asecond diode D₃₂. The first magnetic elements are the inductors L₁, L₂and L₃. The second magnetic elements are transformers T_(x1), T_(x2) andT_(x3). The transformer T_(x1) comprises a primary coil winding N_(p1)and plural secondary coil windings N_(s11) and N_(s12). The transformerT_(x2) comprises a primary coil winding N_(p2) and plural secondary coilwindings N_(s21) and N_(s22). The transformer T_(x3) comprises a primarycoil winding N_(p3) and plural secondary coil windings N_(s31) andN_(s32). The primary coil winding N_(p1) has a first terminal g₁₁ and asecond terminal g₁₂. The primary coil winding N_(p2) has a firstterminal g₂₁ and a second terminal g₂₂. The primary coil winding N_(p3)has a first terminal g₃₁ and a second terminal g₃₂. The shared thirdterminal g₁₃ of the secondary coil windings N_(s11) and N_(s12), theshared third terminal g₂₃ of the secondary coil windings N_(s21) andN_(s22) and the shared third terminal g₃₃ of the secondary coil windingsN_(s31) and N_(s32) are used as center taps. The first terminals of thefirst switch elements S₁₁, S₂₁ and S₃₁ are electrically connected withan input terminal of the power supply system 7. The second terminals ofthe first switch elements S₁₁, S₂₁ and S₃₁ are electrically connectedwith the first terminals of the S₁₂, S₂₂ and S₃₂, respectively. Thefirst terminals of the capacitors C₁, C₂ and C₃ are electricallyconnected with the second terminals of the first switch elements S₁₁,S₂₁ and S₃₁ and the first terminals of the S₁₂, S₂₂ and S₃₂,respectively. The second terminals of the capacitors C₁, C₂ and C₃ areelectrically connected with the first terminals a₁, a₂ and a₃ of theinductors L₁, L₂ and L₃, respectively. The second terminals b₁, b₂ andb₃ of the inductors L₁, L₂ and L₃ are electrically connected with thefirst terminals g₁₁, g₂₁ and g₃₁ of the primary coil windings of thetransformers T_(x1), T_(x2) and T_(x3), respectively. The secondterminals g₁₂, g₂₂ and g₃₂ of the primary coil windings of thetransformers T_(x1), T_(x2) and T_(x3) are electrically connected witheach other. The third terminals g₁₃, g₂₃ and g₃₃ of the secondary coilwindings of the transformers T_(x1), T_(x2) and T_(x3) are electricallyconnected with a common node N. The fourth terminals gin, g₂₄ and g₃₄ ofthe secondary coil windings N_(s11), N_(s21) and N_(s31) of thetransformers T_(x1), T_(x2) and T_(x3) are electrically connected withthe first diodes D₁₁, D₂₁ and D₃₁, respectively. The fifth terminalsg₁₅, g₂₅ and g₃₅ of the secondary coil windings N_(s12), N_(s22) andN_(s32) of the transformers T_(x1), T_(x2) and T_(x3) are electricallyconnected with the second diodes D₁₂, D₂₂ and D₃₂, respectively.Moreover, the inductors L₁, L₂ and L₃ of FIG. 2 may be implemented withthe magnetic assembly 2 of FIG. 2.

Please refer to FIG. 9 and FIG. 8. In this embodiment, the transformersT_(x1), T_(x2) and T_(x3) are implemented with the magnetic assembly 8.The magnetic assembly 8 comprises plural first magnetic cores 61, pluralcoil windings 62, plural second coil windings 67 and a second magneticcore 63. Each first magnetic core 61 comprises a first central leg 64,plural first side legs 65 and a first connection part 66. The componentsof the magnetic assembly 8 and the relationships between thesecomponents are similar to those of the magnetic assembly 2 of the FIG.2. Component parts and elements corresponding to those of the FIG. 2 aredesignated by identical numeral references, and detailed descriptionsthereof are omitted. In comparison with the magnetic assembly 2 of FIG.2, a second coil winding 67 is further wound around the first centralleg 64 of each first magnetic core 61 of the magnetic assembly 8 of thisembodiment. In other words, the first coil winding 62 wound around eachfirst magnetic core 61 is a primary coil winding, and the second coilwinding 67 wound around each first magnetic core 61 is used as secondarycoil windings. Moreover, the secondary coil windings have a center tap.Consequently, the first terminals g₁₁, g₂₁ and g₃₁ of the three firstcoil windings 62 correspond to the first terminal g₁₁ of the transformerT_(x1), the first terminal g₂₁ of the transformer T_(x2) and the firstterminal g₃₁ of the transformer T_(x3), respectively. In addition, thesecond terminals g₁₂, g₂₂ and g₃₂ of the three first coil windings 62correspond to the first terminal g₁₂ of the transformer T_(x1), thefirst terminal g₂₂ of the transformer T_(x2) and the first terminal g₃₂of the transformer T_(x3), respectively. The third terminals g₁₃, g₂₃and g₃₃ of the three second coil windings 67 correspond to the thirdterminals g₁₃, g₂₃ and g₃₃ of the transformers T_(x1), T_(x2) andT_(x3). In some embodiment, each of the first coil winding 62 and thesecond coil winding 67 is composed of plural coil windings. Moreover,the first coil winding 62 and the second coil winding 67 are formed asthe primary coil winding and the secondary coil winding, respectively.

In one embodiment, adjusts the magnetizing inductance values of theprimary coil winding N_(p1), N_(p2) and N_(p3) of the transformersT_(x1), T_(x2) and T_(x3) to be equal, to make the electric currentsflowing through the first coil winding 62 wounding round the firstcentral legs 64 of the three first magnetic cores 61 of the converters71, 72 and 73 to be equal. In one embodiment, adjusts the turns of thefirst coil windings 62 to be equal, to make the magnetizing inductancevalues of the primary coil winding N_(p1), N_(p2) and N_(p3) of thetransformers T_(x1), T_(x2) and T_(x3) to be equal.

The technical features of the other components of the magnetic assembly8 as shown in FIG. 9 are similar to those of the magnetic assembly 2 ofFIG. 2, and are not redundantly described herein.

From the above descriptions, the present invention provides a magneticassembly and a power supply system with the magnetic assembly. Themagnetic assembly comprises plural magnetic elements of pluralconverters. Moreover, portions of the first connection parts of thefirst magnetic cores are shared by adjacent first magnetic cores.Consequently, the magnetic assembly with the plural magnetic elementshas reduced volume and weight, and the fabricating cost is reduced.Moreover, since the inductance values of the magnetic elements are equalor the magnetizing inductance values of the transformers are equal, theplural parallel-connected converters can be controlled more easily.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A power supply system comprising pluralconverters, wherein the plural converters are connected with each otherin parallel, and the plural converters receive an input voltage andconvert the input voltage into an output voltage, wherein the pluralconverters comprise a magnetic assembly, and the magnetic assemblycomprises: plural first magnetic cores stacked over each other frombottom to top, wherein each of the plural first magnetic cores comprisesplural legs and a first connection part, and the first connection partis connected with first terminals of the plural legs, wherein the firstconnection part of the first magnetic core at an upper position islocated adjacent to second terminals of the plural legs of the adjacentfirst magnetic core at a lower position; plural coil windings, whereineach coil winding is wound around at least one leg of the plural legs ofthe corresponding first magnetic core so as to form a magnetic elementof the corresponding converter; and a second magnetic core stacked overthe plural first magnetic cores, wherein the second magnetic core islocated adjacent to the second terminals of the legs of the topmostfirst magnetic core; wherein electric currents flowing through theplural coil windings are in the same direction, and magnetic fluxesthrough the first connection part of the first magnetic core at theupper position, which correspond to two coil windings of two adjacentfirst magnetic cores, are in opposite directions.
 2. The power supplysystem according to claim 1, wherein the plural converters arenon-isolated converters, wherein each non-isolated converter includes aninductor, and the inductor is integrated into the magnetic assembly. 3.The power supply system according to claim 2, wherein the non-isolatedconverter is a boost converter or a buck converter.
 4. The power supplysystem according to claim 1, wherein the plural converters are isolatedconverters, wherein each isolated converter includes a transformer, andthe transformer is integrated into the magnetic assembly.
 5. The powersupply system according to claim 4, wherein the isolated converter is aresonant converter.
 6. The power supply system according to claim 5,wherein the resonant converter is a LLC resonant converter, wherein theLLC resonant converter further comprises a resonant inductor, and theresonant inductor is integrated into the magnetic assembly.